A STUDY ON THERMAL DIFFUSION OF VAPOR IN HUMID AIR

Abstract

The vapor flux caused by temperature difference is estimated with calculation based on molecular dynamics. The thermal diffusion, which is defined in the couple with vapor flux caused by pressure gradient, has been expressed approximately by Chapman and Cowling in the extremely complicated numerical form. The literature survey shows that it has not clarified the degree of the approximation error and actual effect in and around the buildings. The calculation results supported by today's great CPU power shows good agreement with comparative reported results and the higher approximation has not great difference with the first approximated result. And the numerical results show that the thermal diffusion effect is negligible in actual building problems.